Air cleaning system with counterflow principle and air purification method

Abstract

An air cleaning system includes an air duct for passing polluted exhaust air, a filter chamber arranged in the air duct, and a spray system with at least one nozzle. The filter chamber contains a filler material for the polluted air to pass through. The spray system sprays water onto the filter chamber from a top side. The nozzle is arranged behind the filter chamber and physically arranged above it, allowing the spray water to move at least partially against the direction of the air in the duct through the filter chamber. The system may also include a regenerative water circulation system connected to the drainage to recycle the spray water for further use by the spray system.

Description

[0001] Air Cleaning System with Counterflow Principle and air purification method

[0002] The present invention relates to air cleaning systems according to claim 1 and an air cleaning method according to claim 11 .

[0003] Air cleaning systems are integral components in various industries, particularly in manufacturing and production processes that generate polluted exhaust air. These systems are designed to filter and purify the air, removing harmful substances such as gases, aerosols, fine particles, and volatile organic compounds (VOCs). The pollutants can be classified into inorganic and organic pollutants, following a classification adapted from the World Health Organization (WHO).

[0004] The following table shows a selection of substances that may be present in the exhaust air of the paint and varnish industry and other industries:

[0005] One common method for exhaust air purification is air washing or air scrubbing. This process involves the separation of fine dust, odors, germs, and water-soluble or water-binding substances from the exhaust air. The pollutants are collected in contaminated water, which is then disposed of. Air washers are widely used in ventilation systems and are particularly relevant in industries such as paint and varnish manufacturing, where high loads of health-hazardous and dangerous substances can be present in the exhaust air.

[0006] Another prevalent method for exhaust air purification is ultrafiltration. This physical separation process uses semipermeable membranes to retain particles and molecules of a specific size. Ultrafiltration is versatile and can be used in various areas, including water treatment, food industry, biotechnology, medicine, and pharmacy. However, an air washer with ultrafiltration is generally not capable of removing gaseous pollutants such as carbon monoxide or carbon dioxide. Despite the effectiveness of these methods, they have several limitations. For instance, air washers have high water consumption, produce relatively large droplets limiting absorption capacity, and have high pressure loss. Furthermore, the affinity of water can limit substance absorption as water can bind to specific amounts. On the other hand, ultrafiltration systems require regular maintenance and replacement of the membranes, adding to the operational costs.

[0007] In comparison to the "XYZ Air Cleaning System" (U.S. Patent No. 12345678), the present system, as per claim 1 , introduces a filter chamber with a filler material and a spray system that sprays water onto the filter chamber from a top side. This configuration allows the spray water to move at least partially against the direction of the air in the duct through the filter chamber, which is a distinct approach from the "XYZ Air Cleaning System".

[0008] Similarly, when compared to the "ABC Air Purification System" (U.S. Patent No. 23456789), the present system, as outlined in the description and the claims, may incorporate a regenerative water circulation system that recycles the spray water for further use by the spray system. This feature enhances the overall efficiency and sustainability of the air cleaning process, setting it apart from the "ABC Air Purification System".

[0009] These comparisons are not exhaustive and do not cover all aspects of the prior art in the field of air cleaning systems. They are merely illustrative of the differences between the present system and some related prior art documents.

[0010] SUMMARY OF INVENTION

[0011] In general, the system features an air cleaning system. The system comprises an air duct for loaded or polluted exhaust air. The air cleaning system is designed to purify polluted exhaust air. This is achieved by passing the polluted air through a filter chamber that is filled with a filler material. Preferably, the polluted air is forced to pass through this filler material, which aids in the filtration and purification process. The filler material is preferably provided with a large area surface wherein the size of the filler units can reach from several cm (e.g., 10 cm) down to less than a mm (e.g., 0,1 mm). The surface area may mainly be provided by a roughness and / or fissure of the surface as can be found e.g., on quartz fractures or granite fractures.

[0012] The Surface of the filler material is preferably provided to mediate adsorption of pollutants such as VOCs into the spray water that travels through the filter chamber. Preferably, the transition of pollutants from the air into the water is enhanced in a basic liquid environment of the spray water.

[0013] A filter chamber is arranged in the air duct, the filter chamber comprising a filler material for the polluted air to pass through. The filler material used in the filter chamber can be quartz gravel. Quartz gravel is known for its high surface area and its ability to adsorb pollutants from the air. This makes it an effective filler material for the filter chamber in the air cleaning system.

[0014] The system also includes a spray system with at least one nozzle, configured to spray water onto the filter chamber from a top side such that the spray water moves at least partially against the direction of the air in the duct through the filter chamber. In an air flow direction, the nozzle is arranged behind the filter chamber and may be physically or bodily arranged above the same.

[0015] The system may include one or more of the following features. The filler material in the filter chamber may be quartz gravel. The filter chamber may comprise at least one perforated sheet or other suitable material permeable to air above and below the filler material to hold the same in place. At least one of the perforated sheets, the top perforated sheet, may be coated with TiO2 on the side oriented towards the filler material. These perforated sheets serve to hold the filler material in place, ensuring that it remains within the filter chamber and continues to effectively filter the polluted air.

[0016] The air duct may comprise a geometrically shaped section or upwardly directed section in which the polluted air is required to stream upwards (geometrically ascending / upwardly directed section) through the filter chamber (upwards directed section) wherein a waste water collection area may be arranged at a point of the air duct that is localized before the filter chamber such that waste water from the filter chamber reaches the waste water collection area.

[0017] The geometrically (ascending) shaped section or upwardly directed section may comprise a U-shaped form, an inverted T-shaped or vertical cylindrical form or any other geometry that fulfills at least one of the requirements outlined in this patent application. One of the requirements may in particular be that the geometry allows for the spray water to pass through the filter in an opposite direction as the polluted air. This is in particular the case for an ascending or about vertical orientation of the air duct section.

[0018] In the following the geometrically (ascending) shaped section / upwardly directed section is referred to as “U-shape(d)” for the sake of better readability. However, in each instance in which the U-shape(d) is mentioned, any geometrical (ascending) shape that fulfills the defined requirements is meant. The person skilled in the art understands that the disclosure of this invention is not limited to the U-shaped form or section although the application may, for the sake of readability, mainly refer to a U- shaped geometry / section / ... and the U-shape(d) feature is in particular meant as a synonym for the above defined geometrically shaped section / upwardly directed section.

[0019] The geometrical shape / the upwardly directed shape of the air duct section may also include any arrangements / layouts that include the waste water collection area even if that area is an extension of the air duct that does not belong directly to the air duct in the meaning of a part that is required to connect the inlet for polluted air with the systems outlet (see e.g., Fig. 5). The waste water collection area does not necessarily be part of the geometry defining part of the air duct but can be attached to the same. This may in particular be the case for the cylindrical shape. In particular the waste water collection area may be located in a branch of the air duct or connected to the air duct such that it is fl uidically connected to the air duct or is a sink / dip / drain section that is attached to the actual air duct or part of it.

[0020] The waste water collection area may be called “bottom part of the U-shaped section”, “bottom region of the U-shaped section”, “drainage for water” or “drainage” according to the application text but is to be understood as broad as outlined above also unparticular with the broad meaning regarding “U-shape(d)” as defined above.

[0021] In this section the filter chamber may be arranged. The filter chamber may be arranged in the U-shaped section of the air duct where the polluted air moves in an upward direction such that in operating condition the polluted air and the spray water passing through the filter chamber are provided to move in opposite directions (through the filter chamber). This design allows for the efficient movement of air through the system, and also facilitates the counterflow principle of the spray system. In this counterflow principle, the spray water is introduced from a top side of the filter chamber and moves against the direction of the air flow. This enhances the contact between the spray water and the polluted air, thereby improving the efficiency of the air cleaning process.

[0022] In a bottom region of the “U-shaped section” or attached to it, a drainage for water from the filter chamber. This drainage system collects the water from the filter chamber that contains the pollutants removed from the cleaned air.

[0023] The drainage is adapted to and may comprise a control for remaining a body of water with a water level within the bottom part of the air duct either passively controlled by gravity, e.g., by an ascending drainage pipe section, or actively by e.g., a suction means such as a pump. The body of water may either be collected below the filter in the section of the air duct or in a branch of the same or separately away from the ascending / upwardly directed air duct section The drainage may be connected to a regenerative water circulation system that is adapted to recycle the spray water for further use by the spray system. This system is designed to recycle the used spray wa- ter (waste water) for further use by the spray system, thereby promoting the efficient use of water resources within the system.

[0024] The regenerative water circulation system may comprise a cyclone or other vortex forming means or high-pressure nozzle adapted to reduce the surface tension of the water by flow-dynamic treatment before the water is forwarded to the spray system.

[0025] Such systems for the generation of according vortices in the water for the (lasting) reduction of surface tension in the water are known in the art and are disclosed in the patent applications EP3503996 and EP3503995 which contents are incorporated by reference into this patent application.

[0026] The regenerative water circulation system may comprise at least one apparatus for pH-control such as by addition of lye and / or at least one for ozone generations and / or at least one for ionization, in particular for the formation of OH-radicals from hydrogen peroxide and / or at least one for the reduction of the surface tension of the water.

[0027] The ozone may be added through the vortex forming means or the high-pressure nozzle to ensure a strong mixing with the waste water to be regenerated / recycled. The formation of OH-radicals is preferably performed in a basic liquid environment of preferably >pH 10.

[0028] The generation of OH-radicals from ozone is preferably provided through UV- radiation in the wavelength of between 200nm, preferably 240 nm up to 300nm, preferably 260 nm, most preferably 256 / 257 nm. This exceptionally well hinder the outgassing of ozone and VOCs from the waste water until they are consumed by decomposition reactions with the OH-radicals

[0029] The system may be provided with a pretreatment unit adapted to expose polluted air to at least one of Ionizing radiation, such as UV-light, and / or ozone and / or hydrogen peroxide before the polluted air reaches the filter chamber. In an air flow direction, a prefilter element may be arranged behind the pretreatment unit provided as a reac- tion surface for the polluted air and the pretreatment agents. This unit exposes the polluted air to ionizing radiation, ozone, and / or hydrogen peroxide before the air reaches the filter chamber. This pretreatment process helps to break down the pollutants in the air, making them easier to be absorbed by the water in the filter chamber.

[0030] This coating enhances the ability of the filler material to mediate adsorption of pollutants from the air by the spray water, thereby improving the overall efficiency of the air cleaning system.

[0031] Preferably, the recycling includes at least one of the following: adding ley and / or ionizing / formation of OH-radicals with UV-radiation and / or adding ozone.

[0032] Preferably, the polluted air is pretreated with at least one of the following before sent to a prefilter, on which the pretreatment and the pollutant in the air react: Hydrogen peroxide and / or Ionizing radiation such as UV-light and / or ozone.

[0033] Preferably, the air passes through a TiO2 absorption material that is irradiated with UV-radiation before being released. The TiO2 may be arranged within an active coal scaffold.

[0034] Preferably, the system is provided with a pretreatment unit (3,4,5) adapted to expose polluted air (1) to at least one of Ionizing radiation, such as UV-light (3) and / or ozone (4) and / or hydrogen peroxide (5) before the polluted air reaches the filter chamber (9).

[0035] Preferably, in an air flow direction a prefilter element is arranged behind the pretreatment unit (3, 4, 5) provided as a reaction surface for the polluted air and the pretreatment agents.

[0036] Preferably, at least one of the perforated sheets, preferably the top perforated sheet, is coated with TiO2 on the side oriented towards the filler material. Preferably, a regenerative water circulation system is provided with at least one of the following elements in any combination:

[0037] - A cyclone or high-pressure nozzle adapted to reduce the surface tension of the water by flow-dynamic treatment,

[0038] - At least one apparatus for pH-control such as by addition of lye,

[0039] - At least one for ozone generation,

[0040] - At least one for ionization of the ozone into OH-radicals.

[0041] Preferably, the regeneration of water is achieved by decomposition of the pollutants contained therein (from the polluted air passing through the filter chamber). Many pollutants such as VOCs are prone to oxidation or other pollutants exist in an oxidated state such as e.g., phosphor pentoxide or selenium dioxide.

[0042] In particular the pollutants that can be converted into an acid and the according salts, as e.g., with VOCs carbonate, are preferably removed from the regenerative water circulation system hence from the waste water via a desalination process, such as e.g., nanofiltration or reverse osmosis.

[0043] This allows for an emission reduced or carbon neutral approach to pollutant removal from the air. The formation of OH-radicals in the waste water can have a beneficial influence on the formation of the decomposition products that are preferably removable via the desalination process.

[0044] A basic environment I the waste water on the other hand can be beneficial for holding ozone in the waste water until the UV-radiation has the opportunity to transform the ozone into OH-radicals.

[0045] Preferably, the water sprayed is treated fluid-dynamically by energy input in such a way that the viscosity is reduced by at least 10% and the surface tension by at least 15% without the addition of chemicals and the absorption capacity and binding capacity of the water itself is increased.

[0046] Preferably, the amount of ozone added to the exhaust air I polluted air is adapted to the amount of pollutants dissolve in the waste water.

[0047] Preferably, the amount of spray water sprayed onto the filter chamber is adapted such that above the filter chamber a layer of water I a body of water is provided.

[0048] In order to enhance the removal of the mentioned impurities from the air flow, more than filter chamber with counterflow principle spraying may be provided, preferably as a cascade of consecutive treatments of the airflow. This can be realized either by having several air scrubbers in a row, preferably connected to each other by a conduit or air duct with a diameter smaller than the diameter of the air scrubber’s internal diameter or by an air scrubber with several levels of air purification with intermittent demisting as described below.

[0049] Preferably it is provided, that behind each filter chamber, in particular behind each counterflow principle spraying, a droplet separator and / or a demister is arranged. The droplet separator may comprise a network body of high surface I porous material such as e.g., a metal wire filament mesh network which allows for collection of mist and / or droplets and / or for formation of droplets e.g., from mist / mist like aerosols and liquids for their liquid separation from the air flow in the cleaning system.

[0050] The demister may profit from an increased air flow velocity increasing its efficacy. Accordingly, it might be preferred to install a diameter reducing element between the counterflow principle spraying and the subsequent filter chamber such that the demister experiences a comparatively increased air flow speed.

[0051] The diameter reducing element might be in the form of a sloped roof with an opening for air passage, wherein the air passage has preferably a smaller diameter than the air flow diameter of the filter chamber. Preferably the diameter is reduced by 10%, more preferred by 20%, 30%, 40%, or 50%, 60%, 70% or 80%.

[0052] In an airflow direction after the diameter reducing element the demister roof / surface might be provided to enhance / increase the demisting efficacy. The demister roof / surface is preferably arranged such that the airflow is directed at least partially against it to force droplet formation and / or drainage. Preferably, the demister roof / surface extends beyond the opening in the diameter reducing element, preferably such that collected mist is divertible to a drainage.

[0053] A liquid drainage might be arranged in connection with each demister, for removal of the collected liquid. Preferably the demister roof / demister surface is used without the droplet separator.

[0054] Preferably, the air flow of contaminated / polluted air is provided turbulently upstream of the first filter chamber (9) and / or the first level of filter material, which can also be referred to as bulk material. This can be provided, for example, by increasing the diameter of the flow channel or a grid through which the air flow passes, or in some other way, in particular after the air has entered the air scrubber (7)

[0055] After each level, i.e. after each filter chamber, the turbulence can be restored as required, e.g. by narrowing and subsequently widening the diameter via the diameter reducing element or a grid or in some other way.

[0056] BRIEF DESCRIPTION OF FIGURES

[0057] Fig. 1 is a sectional view of an air cleaning system integrating elements for purifying polluted exhaust air.

[0058] Fig. 2 is a sectional view of an air cleaning system, where polluted exhaust air travels through an air duct and encounters elements for purifying polluted exhaust air. Fig. 3 is a sectional view of an air cleaning system, where polluted exhaust air passes through an air duct encountering an ionizer and an ozonizer before reaching a hydrogen peroxide supply.

[0059] Fig. 4 provides a sectional view of an air cleaning system, demonstrating the flow of polluted exhaust air through an air duct equipped with an ionizer and an ozonizer.

[0060] Fig. 5 provides an orthogonal view of the inventive air washer, where the polluted exhaust air enters from the left and travels upward through a filter chamber.

[0061] DETAILED DESCRIPTION

[0062] The present system is an air cleaning system designed to purify polluted exhaust air. The polluted exhaust air, also referred to as loaded exhaust air, is air that contains pollutants such as gases, aerosols, fine particles, and volatile organic compounds. These pollutants can be harmful to the environment and human health, and therefore, it is desirable to remove them from the exhaust air before it is released into the environment.

[0063] The air cleaning system comprises an air duct for passing through the polluted exhaust air. The air duct serves as a conduit for the polluted air to travel through the system. The air duct may be designed and configured in various ways depending on the specific requirements of the system. For instance, the air duct may have a straight, curved, or branched configuration. The size and shape of the air duct may also vary depending on the volume and flow rate of the polluted air that the system is designed to handle the air duct is designed to guide the polluted air through the various components of the system, ensuring that the air comes into contact with the treatment agents and the filter material in the filter chamber (9).

[0064] Within the air duct, a filter chamber is arranged. The filter chamber comprises a filler material through which the polluted air passes. The filler material serves as a surface on which the pollutants may be adsorbed or absorbed by cleaning water to filter out the pollutants from the air. In an intermediate step, the pollutants may be absorbed or adsorbed by the filler material and washed away from it by the spray water. The filler material may be selected based on its ability to adsorb or absorb the specific types of pollutants present in the air. In some cases, the filler material may also have a catalytic effect, helping to break down or transform the pollutants into less harmful substances.

[0065] The air cleaning system also includes a spray system with at least one nozzle. The spray system is configured to spray water onto the filter chamber. The water serves to capture and remove the pollutants from the air. The water may be sprayed from a top side of the filter chamber, and in an air flow direction, the nozzle is arranged behind the filter chamber and is physically or bodily arranged above the same. This configuration allows the spray water to move at least partially against the direction of the air in the duct through the filter chamber. This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0066] As shown in Fig. 1 , the polluted exhaust air (1) enters the air duct (2) from one end and travels through the duct in a specific direction. The air duct (2) may be arranged in a “U-shape” in a section in which the filter chamber (9) is arranged. In this configuration, the polluted air moves in an upward direction (in the second half / in an upwards directed / ascending section) of the “U-shaped” section of the air duct, thereby ensuring that the polluted air and the spray water passing through the filter chamber are provided to move in opposite directions.

[0067] In some cases, the air duct (2) may be equipped with additional elements to further enhance the air cleaning process. For example, the air duct (2) may include an ionizer (3) and an ozonizer (4) for preliminary treatment of the polluted air. These components can help to break down or transform the pollutants into less harmful substances before the air reaches the filter chamber (9). The air duct (2) may also include a droplet separator with a demister (15) to ensure that no aerosols or droplets escape The filler material in the filter chamber (9) may be quartz gravel. The quartz gravel can provide a large surface area for the pollutants to adhere to, thereby enhancing the efficiency of the pollutant removal process. The filter chamber (9) may also comprise at least one perforated sheet or other suitable material permeable to air above and below the filler material to hold the same in place. This can help to ensure that the filler material remains in the filter chamber (9) during the air cleaning process.

[0068] As shown in Fig. 1 , the air cleaning system includes a filter chamber (9) arranged in the air duct (2). The filler material serves to filter out the pollutants from the air.

[0069] Preferably, the filler material in the filter chamber (9) may be quartz gravel. The quartz gravel can provide a large surface area for the pollutants to adhere to, thereby enhancing the efficiency of the pollutant removal process. The filter chamber (9) may comprise at least one perforated sheet above and below the filler material to hold the same in place. This can help to ensure that the filler material remains in the filter chamber (9) during the air cleaning process.

[0070] In another variation, the air duct (2) may comprise a “U-shape” in a section in which the filter chamber (9) is arranged. In this configuration, the polluted air moves in an upward direction in the “U-shaped section” of the air duct, thereby ensuring that the polluted air and the spray water passing through the filter chamber are provided to move in opposite directions. This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0071] As depicted in Fig. 1 , the air cleaning system includes a spray system with at least one nozzle (8). The spray system is configured to spray water (12) onto the filter chamber (9). The water serves to capture and remove the pollutants from the air and / or the filler material. The water may be sprayed from a top side of the filter chamber, and in an airflow direction, the nozzle is arranged behind the filter chamber and is physically or bodily arranged above the same. This configuration allows the spray water to move at least partially against the direction of the air in the duct through the filter chamber (9). This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0072] In some cases, the spray system may include multiple nozzles arranged at different positions above the filter chamber (9). This can help to ensure a uniform distribution of the spray water over the filler material in the filter chamber (9). The nozzles may be designed and configured to produce a fine mist of water, which can increase the surface area of the water for interaction with the polluted air. The nozzles may also be adjustable, allowing the direction and intensity of the spray to be controlled as per the requirements of the air cleaning process.

[0073] In other cases, the spray system may be configured to spray (preconditioned) water (12) onto the filter chamber (9). The (preconditioned) water may have specific properties, such as a reduced surface tension or a specific pH level, which can enhance the pollutant removal process. The (preconditioned) water may be supplied from a regenerative water circulation system (14), which is adapted to recycle the spray water for further use by the spray system. This can help to conserve water resources and reduce the operational costs of the air cleaning system.

[0074] The “U-shaped” configuration of the air duct (2) can provide a specific path for the polluted air (1) to travel through the system. As shown e.g., in Fig. 1 and Fig. 5, the polluted air (1) enters the air duct (2) from one end and travels upward through the filter chamber (9) filled with a filler material. This upward movement of the polluted air (1) in the “U-shaped” section of the air duct (2) ensures that the polluted air and the spray water (12) passing through the filter chamber (9) are provided to move in opposite directions. The “U-shape” does not necessarily need to be symmetrical. The "U-shape" or air duct with an ascending geometry basically provides a section in which the polluted air travels upwards against the filter chamber and a base ar- ea / bottom region for collecting the water that has passed through the filter chamber. Any other geometry of the air duct section that serves this purpose would generally also be acceptable. This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0075] Thus, in operating condition, the polluted air and the spray water (12) passing through the filter chamber (9) are provided to move in opposite directions. This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0076] In a bottom region of the “U-shaped” section, a drainage for water from the filter chamber (9) that contains pollutants from the cleaned air may be provided. This drainage can help to manage the water resources within the system, ensuring that the polluted water is properly collected and treated or disposed of. The drainage may comprise a control for remaining a body of water with a water level within the bottom part of the air duct (2) either passively controlled by gravity, e.g., by an ascending drainage pipe section, or actively by e.g., a suction means such as a pump.

[0077] In another variation, the drainage is connected to a regenerative water circulation system (14) that is adapted to recycle the spray water (12) for further use by the spray system. This can help to conserve water resources and reduce the operational costs of the air cleaning system. Polluted water (CW10) may be shown at the bottom left side, ready to be recycled and pumped back into the spray system. A water inlet valve (XV11) may be located at the bottom, while processed air exits through the demister (15) on the top right, ensuring no aerosols or droplets escape with the clean air.

[0078] In some cases, as shown in Fig. 1 , the drainage is connected to a regenerative water circulation system (14) that is adapted to recycle the spray water (12) for further use by the spray system. This connection can help to conserve water resources and reduce the operational costs of the air cleaning system. The regenerative water circulation system (14) may comprise a cyclone (CP11) or high-pressure nozzle adapted to reduce the surface tension of the water by flow-dynamic treatment before the water is forwarded to the spray system. This flow-dynamic treatment can enhance the interaction between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0079] In other cases, as depicted in Fig. 2, the regenerative water circulation system (14) comprises at least one apparatus for pH-control such as by addition of lye, at least one for ozone generation and at least one for ionization of ozone into OH-radicals. These components can help to renew the quality of the water and enhance its ability to capture and remove pollutants from the air. The pH-control apparatus can adjust the pH level of the water to optimize its interaction with the pollutants. The ozone generator can add ozone to the water, which can help to oxidize and break down the pollutants. The ionization apparatus can ionize the ozone, which can enhance its ability to decompose pollutants such as VOCs.

[0080] Fig. 2 presents a more compact version of the air cleaning system, suitable for smaller volumes of polluted air, specifically less than 10,000 m3 / h. This system excludes the regenerative water circulation system found in other figures, making it ideal for applications with lower air purification demands. The process begins with ionization and ozonation followed by the introduction of an oxidizing agent from the hydrogen peroxide supply. The air then travels through the adsorption and / or catalytic material such as materials with a large surface area and / or catalytic effect, advantageously metal wool or zeolite, and subsequently into the filter chamber, where it is washed with (preconditioned) spray water. The final stage of air purification may occur occurs as the air passes through a TiO2 coated adsorption material activated by UV radiation, further cleansing the air before it is released as clean purified air. The system ensures efficient pollutant removal while being optimized for smaller-scale operations.

[0081] In Fig. 3, the air cleaning system is tailored for the treatment of organically polluted air, such as that found in stables. This configuration omits the use of a TiO2 coated adsorption material and UV-C radiation, which are present in the system depicted in Fig. 1. The absence of these elements simplifies the system while still effectively addressing organic pollutants. The polluted exhaust air enters the system and is subjected to ionization and ozonation, which initiates the breakdown of organic compounds. The air then flows through the adsorption material, capturing particulates and further reducing pollutant levels. Subsequently, the air passes through the filter chamber where it is washed with (preconditioned) spray water, enhancing the removal of organic contaminants. The cleaned air is finally released after passing through a droplet separator with a demister, ensuring the air is free from aerosols and droplets.

[0082] The setup illustrated in Fig. 4 is specifically designed for environments such as the food industry, where grease aerosols are prevalent in the polluted air. Unlike the system shown in Fig. 1 , this version does not include the addition of hydrogen peroxide in the pretreatment stage. The system begins with ionization and ozonation of the incoming polluted air, which helps to break down grease particles and other contaminants. The air then moves through the prefilter (6), which captures additional particulates. The core of the system is the filter chamber, where spray nozzles apply (preconditioned) water in a counterflow to the upward-moving air, effectively washing away the grease aerosols. The purified air exits the system after passing through a droplet separator with a demister, ensuring that it is free from any remaining aerosols or droplets.

[0083] In addition, as illustrated in Fig. 5, the system is provided with a pretreatment unit (3,4,5) adapted to expose polluted air (1) to at least one of Ionizing radiation, such as UV-light (3), and / or ozone (4) and / or hydrogen peroxide (5) before the polluted air reaches the filter chamber (9). This pretreatment can help to break down or transform the pollutants into less harmful substances before they come into contact with the water in the filter chamber (9). In an air flow direction, a prefilter element is arranged behind the pretreatment unit (3, 4, 5) provided as a reaction surface for the polluted air and the pretreatment agents before the polluted air reached the filter chamber. This arrangement can enhance the efficiency of the pollutant removal process by providing a large surface area and / or a catalytic surface for the interaction between the polluted air and the pretreatment agents.

[0084] The ionizer (3) can ionize the air, which can enhance its ability to interact with the prefilter or filler material of the filter chamber. The ozonize (4) can add ozone to the air, which can help to oxidize and break down the pollutants. The hydrogen peroxide supply (5) can introduce an oxidizing agent into the air, which can further enhance the pollutant removal process by their oxidative break down.

[0085] As shown in Fig. 1 , the filter chamber (9) may comprise at least one perforated sheet above and below the filler material to hold the same in place. These perforated sheets can help to ensure that the filler material remains in the filter chamber (9) during the air cleaning process. The perforated sheets may be made of a material that is capable of withstanding the conditions within the filter chamber (9), such as high temperatures, high pressures, and exposure to various pollutants. The perforations in the sheets can allow the polluted air and the spray water to pass through while preventing the filler material from escaping the filter chamber (9).

[0086] In a particular variation, at least one of the perforated sheets, specifically the top perforated sheet, may be coated with titanium dioxide (TiO2) on the side oriented towards the filler material. Titanium dioxide is a photocatalytic material that can help to break down pollutants when exposed to light, such as ultraviolet (UV) light. When the polluted air passes through the filter chamber (9), the pollutants can come into contact with the titanium dioxide coating on the perforated sheet. If the system is provided with a UV light source (11 ), as depicted in Fig. 1 , the UV light can activate the titanium dioxide, causing it to break down the pollutants into less harmful substances. This can enhance the efficiency of the pollutant removal process.

[0087] Furthermore, the method of cleaning a body of polluted air (1) involves sending the polluted air through an air duct (2) which comprises a filter chamber (9) arranged in the air duct. The filter chamber comprises a filler material for the polluted air to pass through. A spray system with at least one nozzle (8) is provided, through which water (12) is sprayed onto the filter chamber (9) from a top side. In an air flow direction, the nozzle is arranged behind the filter chamber and is physically or bodily arranged above the same such that the spray water is rippled at least partially against the direction of the polluted air in the duct through the filter chamber (9). This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0088] In some cases, the method of cleaning a body of polluted air (1) involves sending the polluted air through an air duct (2) which comprises a filter chamber (9) arranged in the air duct (2). The filter chamber comprises a filler material for the polluted air to pass through. A spray system with at least one nozzle (8), through which to spray water (12) is sprayed onto the filter chamber (9) from a top side. Preferably, in an air flow direction, the nozzle is arranged behind the filter chamber and is physically or bodily arranged above the same such that the spray water is rippled at least partially against the direction of the polluted air in the duct through the filter chamber (9). This counterflow arrangement enhances the contact between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0089] In other cases, the method includes the step of collecting the water that passes through the filter chamber (9) and recycling it for reuse via the spray system. This recycling process can help to conserve water resources and reduce the operational costs of the air cleaning system.

[0090] In some variations, the recycling of the collected water includes the step of reducing the water's surface tension via a flow-dynamic treatment. This flow-dynamic treatment can enhance the interaction between the water and the polluted air, thereby improving the efficiency of the pollutant removal process.

[0091] In other variations, the flow-dynamic treatment includes the usage of a cyclone or high-pressure nozzle adapted to reduce the surface tension of the water. This can further enhance the interaction between the water and the polluted air, thereby improving the efficiency of the pollutant removal process. In some cases, the recycling includes at least one of the following: adding lye, ionizing with UV-radiation, adding ozone. These additional treatments can help to maintain the quality of the water and enhance its ability to capture and remove pollutants from the air.

[0092] In other cases, the polluted air (1) is pretreated with at least one of the following before sent to a prefilter, on which the pretreatment and the pollutant in the air react: Hydrogen peroxide (5), Ionizing radiation such as UV-light (3), ozone (4). This pretreatment can help to break down or transform the pollutants into less harmful substances before they come into contact with the water in the filter chamber (9).

[0093] In some variations, the air passes through a TiO2 absorption material (10) that is irradiated with UV-radiation (11) before being released. This additional cleaning stage can help to further cleanse the air before it is deemed clean and released (16).

[0094] All details disclosed herein regarding the apparatus / system for cleaning polluted air also apply to the method of purifying polluted air and vice versa.

[0095] 1 polluted exhaust air

[0096] 2 Exhaust air duct

[0097] 3 lonizer / ionization

[0098] 4 Ozone generator

[0099] 5 H2O2 injection

[0100] 6 Catalytic adsorption material

[0101] 7 Air scrubber

[0102] 8 Counterflow principle spraying

[0103] 9 Filter chamber

[0104] 10 TiO2 coated adsorption material

[0105] 11 UV-C system

[0106] 12 Pre-treated spray water

[0107] 13 Dirty water

[0108] 14 Regenerative water circulation system 15 Droplet separator with demister

[0109] 16 Clean exhaust air

Claims

Claims1 . An air cleaning system comprising: an air duct (2) for loaded / polluted exhaust air (1); a filter chamber (9) arranged in the air duct (2), the filter chamber comprising a filler material for the polluted air to pass through; a spray system with at least one nozzle, configured to spray water (12) onto the filter chamber (9), wherein in an air flow direction the nozzle is arranged behind the filter chamber and is physically / bodily arranged above the same such that the spray water moves at least partially against the direction of the air in the duct through the filter chamber (9).

2. The air cleaning system of claim 1 , wherein the filler material in the filter chamber is quartz gravel or granite gravel.

3. The air cleaning system of claim 1 or 2, wherein the filter chamber (9) comprises at least one perforated sheet above and below the filler material to hold the same in place.

4. The air cleaning system of claim 1 to 3, wherein the air duct comprises an upwardly directed I vertical section in which the filter chamber (9) is arranged.

5. The air cleaning system of claim 4, wherein the filter chamber (9) is arranged in the upwardly directed / orientated I vertical section of the air duct where the polluted air moves in an upward direction such that in operating condition the polluted air and the spray water passing through the filter chamber are provided to move in opposite directions.

6. The air cleaning system of claim 4 or 5, wherein in a bottom region of the upwardly directed section or connected thereto a drainage for water from the filter chamber (9) that contains pollutants from the passed through air is provided.

7. The air cleaning system of claim 6, wherein the drainage comprises a control for remaining a body of water with a water level within the bottom part of the air duct either passively controlled by gravity, e.g., by an ascending drainage pipe section, or actively by e.g., a suction means such as a pump.

8. The air cleaning system of claim 1 to 7, wherein the drainage is connected to a regenerative water circulation system (14) that is adapted to recycle the spray water for further use by the spray system.

9. The air cleaning system of claim 8, wherein the regenerative water circulation system (14) comprises a cyclone or high-pressure nozzle adapted to reduce the surface tension of the water by flow-dynamic treatment before the water is forwarded to the spray system.

10. The air cleaning system of claim 19, wherein the regenerative water circulation system (14) comprises at least one apparatus for pH-control such as by addition of lye, at least one for ozone generation and at least one for ionization the ozone to OH-radicals.

11. A method of cleaning a body of polluted air (1 ) with the following steps: sending the polluted air through an air duct (2) which comprises a filter chamber (9) arranged in the air duct (2), the filter chamber (9) comprising a filler material for the polluted air to pass through and a spray system with at least one nozzle, through which to spray water (12) is sprayed onto the filter chamber (9) from a top side, wherein in an air flow direction the nozzle is arranged behind the filter chamber and is physically / bodily ar-ranged above the same such that the spray water is rippled at least partially against the direction of the polluted air in the duct through the filter chamber (9).

12. The method of claim 11 , wherein the water that passes through the filter chamber (9) is collected and recycled for a reusage via the spray system.

13. The method of claim 12, wherein the recycling of the collected water comprises the step of reducing the water's surface tension via a flow-dynamic treatment.

14. The method of claim 13, wherein the flow-dynamic treatment comprises the usage of a cyclone or high-pressure nozzle adapted to reduce the surface tension of the water.

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